The present invention relates to a cleaning device to be used in machines for harvesting sugar cane or similar products, or in independent cleaning systems for sugar cane billets, which previously were manually or mechanically harvested. More specifically, the invention relates to harvesting machines of the cutting, chopping, cleaning and loading type which are used in the harvesting of sugar cane "in natura" and burned conditions.
One of the major problems still found nowadays in the sugar cane mechanized harvesting, specially in the chopping-loading harvesters, is the final product quality in relation to the amount of trash contained in the product. The word "trash", as herein used, means soil, sand, vegetal impurities, mainly leaves, tips and roots of sugar cane.
The known harvesters of the chopping throwing-loading type have cleaning systems provided with fans which produce air flows in a transverse or opposite direction in relation to the billet path. During the throwing-loading path of the cane billets with associated trash to the transport vehicle, the cane billets suffer the action of the air flow from the fans causing a separation between the cane billets and the trash. During this separation the cane billets, which are heavier than the trash, proceed in their path towards said vehicle, and the trash, which is lighter, is drawn by the air flow through a side or vertical outlet provided in a load guiding duct of the harvester.
When employed in the harvesting of burned sugar cane, such system presents satisfactory trash rates, reaching values ranging from 3% to 6%, by weight of transported load. However, in non-burned cane harvesting, such values increase substantially, ranging between 12% and 18% by weight, increasing the transportation costs and the fiber content in the milled material in the plant, with a consequent operational yield decrease.